initial build-vm feature

Yes, mkimage-profiles is now able to build VM disk images.
So far the support is pretty basic:

- a single hard drive image with a single partition/FS
- only stock root password is configurable
- LILO is hardwired as a bootloader

The resulting images tend to boot under qemu/kvm though.

Please see doc/vm.txt for the warning regarding additional
privileges and setup required.  This was started back in
February but I still hoped to avoid sudo/privileged helper
(and libguestfs is almost as undistributable as can be)...

Thanks:

- http://blog.quinthar.com/2008/07/building-1gb-bootable-qemu-image-using.html
- Alexey Morarash who reworked that as https://github.com/tuxofil/linsygen
- led@, legion@, vitty@, aen@ for providing advice and inspiration

README

@@ -32,7 +32,7 @@ Most docs are in Russian, welcome to learn it or ask for English.
 - сборка образа
 
 Объекты:
-- дистрибутивы и виртуальные окружения:
+- дистрибутивы и виртуальные среды/машины:
   + описываются в conf.d/*.mk или соответственно lib/{distro,ve}.mk
   + могут основываться на предшественниках, расширяя их
   + дистрибутивы также:

bin/tar2vm

@@ -0,0 +1,130 @@
+#!/bin/sh -e
+
+. shell-error
+
+if [ $# -lt 2 ]; then
+	fatal "error: tar2vm needs at least two arguments"
+fi
+
+# this needs env_keep sudo setup to actually work
+if [ -n "$GLOBAL_BUILDDIR" ]; then
+	WORKDIR="$GLOBAL_BUILDDIR/vmroot"
+else
+	WORKDIR="$(mktemp --tmpdir -d vmroot-XXXXX)"
+fi
+
+[ -n "$WORKDIR" ] || fatal "couldn't come up with suitable WORKDIR"
+
+[ -n "$GLOBAL_DEBUG" ] || message "WORKDIR: $WORKDIR"
+
+# a tarball containing chroot with a kernel
+TAR="$1"
+[ -s "$TAR" ] || fatal "source tarball doesn't really exist"
+
+# a path to the image to be generated
+IMG="$2"
+[ -d "$(dirname "$IMG")" ] || fatal "target directory doesn't exist"
+
+# image size in bytes (256M is a fallback)
+TARSIZE="$(stat -Lc %s "$TAR")"
+DEFSIZE="$(expr 3 '*' "$TARSIZE" '/' 2)"
+DISKSIZE="${3:-${DEFSIZE:-268435456}}"
+# ...and in megabytes
+DISKSIZEM="$(expr "$DISKSIZE" / 1048576)"
+
+# tested to work: ext[234], jfs
+ROOTFSTYPE="${4:-ext4}"
+
+# single root partition hardwired so far,
+# add another image for swap if needed
+ROOTDEV="/dev/sda1"
+
+# last preparations...
+for i in losetup parted kpartx mkfs."$ROOTFSTYPE"; do
+	if ! type -t "$i" >&/dev/null; then
+		fatal "$i required but not found"
+	fi
+done
+
+LOOPDEV="$(losetup --find)"
+ROOTFS="$WORKDIR/chroot"
+
+exit_handler()
+{
+	rc=$?
+	if [ -n "$ROOTFS" ]; then
+		umount "$ROOTFS"{/dev,/proc,/sys,}
+		if [ -n "$LOOPDEV" ]; then
+			kpartx -d "$LOOPDEV"
+			losetup --detach "$LOOPDEV"
+		fi
+		rm -r -- "$ROOTFS"
+		rmdir -- "$WORKDIR"
+	fi
+	exit $rc
+}
+
+trap exit_handler EXIT
+
+# prepare disk image and a filesystem inside it
+rm -f -- "$IMG"
+dd if=/dev/zero of="$IMG" bs=1 count=1 seek="$DISKSIZE" conv=notrunc
+losetup "$LOOPDEV" "$IMG"
+
+parted --script "$LOOPDEV" mklabel msdos
+parted --script "$LOOPDEV" mkpart primary ext2 1 "$DISKSIZEM"
+
+kpartx -a "$LOOPDEV"
+LOOPDEV1="/dev/mapper/$(basename "$LOOPDEV")p1"
+
+mkfs."$ROOTFSTYPE" "$LOOPDEV1"
+
+# mount and populate it
+mkdir -pm755 "$ROOTFS"
+mount "$LOOPDEV1" "$ROOTFS"
+tar -C "$ROOTFS" --numeric-owner -xf "$TAR"
+for i in /dev /proc /sys; do mount --bind "$i" "$ROOTFS$i"; done
+
+# NB: different storage modules might be needed for non-kvm
+echo "$LOOPDEV1 / $ROOTFSTYPE defaults 1 1" >> "$ROOTFS/etc/fstab"
+echo "MODULES_PRELOAD=sd_mod ata_piix $ROOTFSTYPE" >> "$ROOTFS/etc/initrd.mk"
+
+KERNEL="$(readlink $ROOTFS/boot/vmlinuz | sed 's,vmlinuz-,,')"
+chroot "$ROOTFS" make-initrd -k "$KERNEL"
+
+sed -i "s,$LOOPDEV1,$ROOTDEV," "$ROOTFS/etc/fstab"
+
+# configure and install bootloader
+REGEXP='^([0-9]+) heads, ([0-9]+) sectors/track, ([0-9]+) cylinders.*$'
+set -- $(fdisk -l "$LOOPDEV" | grep -E "$REGEXP" | sed -r "s@$REGEXP@\1 \2 \3@")
+
+LILO_COMMON="lba32
+delay=1
+vga=0
+image=/boot/vmlinuz
+  initrd=/boot/initrd.img
+  append=\"root=$ROOTDEV rootdelay=3\"
+  label=linux"
+
+cat > "$ROOTFS"/etc/lilo-loop.conf << EOF
+boot=$LOOPDEV
+disk=$LOOPDEV
+  bios=0x80
+  heads=$1
+  sectors=$2
+  cylinders=$3
+  partition=$LOOPDEV1
+  start=63
+$LILO_COMMON
+EOF
+
+chroot "$ROOTFS" lilo -C /etc/lilo-loop.conf
+
+cat > "$ROOTFS"/etc/lilo.conf << EOF
+boot=${ROOTDEV%[0-9]*}
+$LILO_COMMON
+EOF
+
+if [ -n "$SUDO_USER" ]; then
+	chown "$SUDO_USER" "$IMG" "$ROOTFS" "$WORKDIR"
+fi

doc/variables.txt

@@ -76,6 +76,11 @@
   + NB: в силу специфики обработки передаётся только явно
   + см. ../Makefile, ../report.mk, ../lib/report.mk
 
+- ROOTPW
+  + устанавливает пароль root по умолчанию для образов виртуальных машин
+  + значение: пусто (по умолчанию root) либо строка
+  + см. ../features.in/build-vm/image-scripts.d/00root
+
 - SAVE_PROFILE
   + сохраняет архив сгенерированного профиля в .disk/
   + значение: пусто (по умолчанию) либо любая строка

doc/vm.txt

@@ -0,0 +1,20 @@
+сборка образов виртуальных машин
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ВНИМАНИЕ: заключительная операция создания образа жёсткого диска
+из архива с содержимым корневой файловой системы требует доступа
+к sudo и разрешения на выполнение скрипта bin/tar2vm в корневом
+каталоге метапрофиля при установке mkimage-profiles из пакета.
+
+Соответствующий фрагмент конфигурации sudo(8) может выглядеть как:
+
+mike ALL=NOPASSWD: /usr/share/mkimage-profiles/bin/tar2vm
+
+При работе с git следует иметь в виду, что предоставлять недоверенному
+пользователю право выполнять с повышенными привилегиями доступный ему
+по записи скрипт равнозначно предоставлению полных привилегий root.
+
+Также потребуется пакет multipath-tools (/sbin/kpartx).
+
+Пример сборки и запуска VM:
+
+$ make ROOTPW=reallysecret1 vm/bare.img && kvm -hda ~/out/bare.img

features.in/build-distro/lib/90-build-distro.mk

@@ -23,7 +23,6 @@ all: $(GLOBAL_DEBUG) prep copy-subdirs copy-tree run-scripts pack-image \
 	postprocess $(GLOBAL_CLEAN_WORKDIR)
 
 prep: $(GLOBAL_DEBUG) dot-disk $(WHATEVER) imagedir
-#prep: $(GLOBAL_DEBUG) dot-disk metadata imagedir
 
 dot-disk:
 	@mkdir -p files/.disk

features.in/build-vm/README

@@ -0,0 +1,3 @@
+Эта фича конфигурирует создание образа виртуальной машины (VM).
+Дополняет финальную стадию сборки (lib/, image-scripts.d/).
+Требует для работы sudo(8) -- см. тж. ../../doc/vm.txt .

features.in/build-vm/config.mk

@@ -0,0 +1,3 @@
+# hooked from ../../lib/sugar.mk
+use/build-vm:
+	@$(call add_feature)

features.in/build-vm/image-scripts.d/00root

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+ROOTPW="${GLOBAL_ROOTPW:-root}"
+
+if type -t chpasswd >&/dev/null; then
+	echo "root:$ROOTPW" | chpasswd
+fi

features.in/build-vm/image-scripts.d/03services

@@ -0,0 +1,9 @@
+#!/bin/sh
+# VMs might have no means to communicate with the outer
+# world except for networking
+
+[ -x /sbin/chkconfig ] || exit 0
+
+for i in network random syslogd; do chkconfig $i on; done
+for i in fbsetfont netfs rawdevices; do chkconfig $i off; done
+:

features.in/build-vm/image-scripts.d/04inittab

@@ -0,0 +1,4 @@
+#!/bin/sh -e
+# we don't need no extra gettys in VMs
+[ -s /etc/inittab ] || exit 0
+sed -i 's,^[3-9]\+:[0-9]\+:respawn:/sbin/mingetty.*,#&,' /etc/inittab

features.in/build-vm/image-scripts.d/06syslog

@@ -0,0 +1,16 @@
+#!/bin/sh -e
+# tweak syslog configuration to:
+# - avoid logging to a nonexistent tty;
+# - avoid hard sync logging (one is better off doing
+#   remote syslog if you do care for reliable data anyways)
+# credits: vvk@, thresh@ (2010)
+
+CONFIG=/etc/syslog.conf
+
+[ ! -f "$CONFIG" ] || \
+	sed -i \
+		-e 's,/dev/tty12,/var/log/syslog/console,' \
+		-e 's,^.*/var/log/syslog/console$,#&,' \
+		-e 's,-/var/log/,/var/log/,g' \
+		-e 's,/var/log/,-/var/log/,g' \
+		"$CONFIG"

features.in/build-vm/image-scripts.d/07kernel

@@ -0,0 +1,13 @@
+#!/bin/sh
+# predictable file locations make bootloader configuration simple;
+# this script relates to .../features.in/stage2/stage1/scripts.d/80-make-initfs
+
+kver="$(rpm -qa 'kernel-image*' \
+            --qf '%{installtime} %{version}-%{name}-%{release}\n' \
+        | sort -n \
+        | tail -n 1 \
+        | cut -f 2 -d ' ' \
+        | sed 's/kernel-image-//')"
+
+ln -s vmlinuz-$kver /boot/vmlinuz
+ln -s initrd-$kver.img /boot/initrd.img

features.in/build-vm/lib/90-build-vm.mk

@@ -0,0 +1,33 @@
+# step 4: build the virtual machine image
+
+IMAGE_PACKAGES = $(SYSTEM_PACKAGES) \
+		 $(COMMON_PACKAGES) \
+		 $(BASE_PACKAGES) \
+		 $(THE_PACKAGES) \
+		 $(call list,$(BASE_LISTS) $(THE_LISTS)) \
+		 $(call kpackages,$(THE_KMODULES) $(BASE_KMODULES),$(KFLAVOURS))
+
+# intermediate chroot archive
+VM_TARBALL := $(IMAGE_OUTDIR)/$(IMAGE_NAME).tar
+
+check-sudo:
+	@if ! type -t sudo >&/dev/null; then \
+		echo "** error: sudo not available, see doc/vm.txt" >&2; \
+		exit 1; \
+	fi
+
+convert-image: check-sudo
+	@if ! sudo $(TOPDIR)/bin/tar2vm \
+		"$(VM_TARBALL)" "$(IMAGE_OUTPATH)" $$VM_SIZE; then \
+		echo "** error: sudo tar2vm failed, see also doc/vm.txt" >&2; \
+		exit 1; \
+	fi
+
+run-image-scripts: GLOBAL_ROOTPW := $(ROOTPW)
+
+pack-image: MKI_PACK_RESULTS := tar:$(VM_TARBALL)
+
+all: $(GLOBAL_DEBUG) build-image copy-tree run-image-scripts pack-image \
+	convert-image postprocess $(GLOBAL_CLEAN_WORKDIR)
+
+prep: imagedir

features.in/pack/config.mk

@@ -1,3 +1,4 @@
+# distributions
 DISTRO_EXTS := .iso
 
 use/pack:
@@ -12,6 +13,7 @@ else
 	@$(call set,IMAGE_PACKTYPE,isodata)
 endif
 
+# virtual environments
 VE_ARCHIVES := tar cpio
 VE_COMPRESSORS := gz xz# there's no sense in bzip2 by now
 VE_ZIPS := $(call addsuffices, \
@@ -34,3 +36,8 @@ $(foreach c,$(VE_ARCHIVES), \
 	$(eval $(call PACK_containers,$(c))) \
 	$(foreach z,$(VE_COMPRESSORS), \
 		$(eval $(call PACK_compressors,$(c),$(z)))))
+
+# virtual machines
+VM_EXTS := .img
+
+use/pack/img: use/pack; @:

lib/help.mk

@@ -6,7 +6,7 @@ define help_body
 endef
 else
 define help_body
-	@echo '** available $(1) targets:'; \
+	echo '** available $(1) targets:'; \
 	columnize $(2)
 endef
 endif
@@ -14,11 +14,15 @@ endif
 help = $(and $(2),$(help_body))
 
 help/distro:
-	$(call help,distribution,$(sort $(DISTROS:distro/%=%)))
+	@$(call help,distribution,$(sort $(DISTROS:distro/%=%)))
 
 help/ve:
-	@echo '** available virtual environment targets:'; \
-	columnize $(sort $(VES))
+	@[ -n "$(SPACE)" ] && echo; \
+	$(call help,virtual environment,$(sort $(VES)))
 
-help: | help/distro help/space help/ve; @:
-help/space:; @echo
+help/vm:
+	@[ -n "$(SPACE)" ] && echo; \
+	$(call help,virtual machine,$(sort $(VMS)))
+
+help: SPACE = 1
+help: help/distro help/ve help/vm; @:

lib/vm.mk

@@ -0,0 +1,17 @@
+# step 2: build up virtual machine's configuration
+
+ifndef MKIMAGE_PROFILES
+$(error this makefile is designed to be included in toplevel one)
+endif
+
+ifeq (vm,$(IMAGE_CLASS))
+
+#vm/.bare: profile/bare use/bootloader/grub
+vm/.bare: profile/bare
+	@$(call add,BASE_PACKAGES,basesystem interactivesystem lilo passwd shadow-utils e2fsprogs mingetty)
+	@$(call set,KFLAVOURS,std-def)
+
+vm/bare: vm/.bare
+	@$(call add,BASE_PACKAGES,apt)
+
+endif

main.mk

@@ -34,15 +34,19 @@ include lib/*.mk
 include conf.d/*.mk
 include features.in/*/config.mk
 
+# starts to look copypastey
 DISTRO_TARGETS := $(shell sed -n 's,^\(distro/[^:.]\+\):.*$$,\1,p' \
 		lib/distro.mk $(wildcard conf.d/*.mk) | sort -u)
 VE_TARGETS := $(shell sed -n 's,^\(ve/[^:.]\+\):.*$$,\1,p' \
 		lib/ve.mk $(wildcard conf.d/*.mk) | sort -u)
+VM_TARGETS := $(shell sed -n 's,^\(vm/[^:.]\+\):.*$$,\1,p' \
+		lib/vm.mk $(wildcard conf.d/*.mk) | sort -u)
 DISTROS := $(call addsuffices,$(DISTRO_EXTS),$(DISTRO_TARGETS))
 VES     := $(call addsuffices,$(VE_EXTS),$(VE_TARGETS))
-IMAGES  := $(DISTROS) $(VES)
+VMS     := $(call addsuffices,$(VM_EXTS),$(VM_TARGETS))
+IMAGES  := $(DISTROS) $(VES) $(VMS)
 
-.PHONY: $(IMAGES) $(DISTRO_TARGETS) $(VE_TARGETS)
+.PHONY: $(IMAGES) $(DISTRO_TARGETS) $(VE_TARGETS) $(VM_TARGETS)
 .PHONY: debug everything help space
 
 ### duplicate but still needed